I said when the OP was 5 minutes old, the game would start. That post was at 23:00:41, meaning the only posts that counted came after 23:05:41. This means that Charmander, Mew, Charizard, Charmander again, and Muk did not count.

This also means that the challenge ended at 23:10:41. Lol@ Krabby being posted at exactly the end time.